Fiber optic termination system

ABSTRACT

A fiber optic telecommunications frame is provided including termination modules positioned on left and right sides of the frame. The frame further includes left and right vertical cable guides. The frame includes a horizontal passage linking the left and right panels and the cable guides. The termination modules hold fiber optic modules with front termination locations. The fiber optic modules can house couplers, such as splitters, combiners, and wave length division multiplexers. A retention mechanism retains each fiber optic module in a partially removed position from the termination module.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 12/911,404,filed Oct. 25, 2010, which is a continuation of application Ser. No.12/495,355, filed Jun. 30, 2009, now U.S. Pat. No. 7,822,313, which is acontinuation of application Ser. No. 12/077,801, filed Mar. 20, 2008,now U.S. Pat. No. 7,555,193, which is a continuation of application Ser.No. 11/411,414, filed Apr. 25, 2006, now U.S. Pat. No. 7,367,823, whichis a divisional of application Ser. No. 11/151,932, filed Jun. 13, 2005,now U.S. Pat. No. 7,142,765, which is a divisional of application Ser.No. 10/745,918, filed Dec. 23, 2003, now U.S. Pat. No. 6,920,274, whichapplications are incorporated herein by reference in their entirety.

FIELD

This invention pertains to the telecommunications industry. Moreparticularly, this invention pertains to a high-density fiberdistribution frame for use in the telecommunications industry.

BACKGROUND

In the telecommunications industry, use of fiber optic cables forcarrying transmission signals is rapidly growing. To connect fiber opticequipment, fiber distribution frames have been developed. Examples ofprior art fiber distribution frames are shown in commonly assigned U.S.Pat. Nos. 4,995,688; 5,497,444; and 5,758,003 to ADC Telecommunications,Inc. In each of the fiber distribution frames of the prior patents, aplurality of adapters are provided which permit attachment of fiberoptic connectors to both sides of each adapter in order to opticallycouple two fiber optic cables. Cables from the adapters are connected tovarious pieces of fiber optic equipment. Using patch cords or cablesbetween the adapters, the pieces of optical equipment are thencross-connected through the frame. The frame defines a demarcation pointbetween the equipment.

The use of modular fiber optic connector modules is known for performingso-called cross-connect applications. U.S. Pat. Nos. 5,432,875;5,363,465; and 6,208,796 to ADC Telecommunications, Inc. concern fiberoptic connector modules and chassis designs for receiving the modules incross-connect applications.

U.S. Pat. No. 6,556,763 also to ADC Telecommunications, Inc., concerns afiber distribution frame with connector modules. The connector modulesof the '763 patent slide into termination modules held by the frame.

Notwithstanding advances previously made in the art, there is acontinuous need for further advances to maintain a high-density ofconnector terminals. There are further needs for ready access to thefiber optic connectors and couplers, enhanced fiber management, andavoidance of excessive bending and stresses on the fiber optic cables.

SUMMARY

The present invention relates to a fiber optic termination module orchassis comprising a housing having first and second spaced apart ends,and first and second spaced apart sides extending between the ends. Thehousing includes a rear extending between the first and second ends, andthe first and second sides to define an interior. The housing defines anopen front, with the first and second ends extending generallyhorizontally, and the first and second sides extending generallyvertically when the termination module is mounted to thetelecommunications rack. The termination module slideably receivesmodular fiber optic units or fiber optic modules through the open front.The fiber optic modules include fiber optic connection locations on thefront, such as adapters for connecting to cables, and fiber opticcircuitry disposed within the interior of the fiber optic module. Thetermination module, which receives the fiber optic module, preferablyincludes shelves, slides, guides, or other structure for holding eachmodule. A retention mechanism allows a selected fiber optic module toslide partially outwardly from the termination module to a retainedposition to allow access to the front connection locations withoutinterfering with the connection locations of adjacent fiber opticmodules. Preferably, the fiber optic modules are at a non-perpendicularangle relative to a plane defined by the rear of the termination module.

A further aspect of the present invention relates to a fiber opticmodule including a housing having two spaced-apart major sidesinterconnected by two spaced-apart minor sides, and a rear. A pluralityof adapters are provided on a front of the housing for use in connectingto cable connectors. Circuiting is disposed within the housing forconnecting the front adapters. The module preferably includes at leastone side flange extending from one of the major sides, and at least onefront flange extending from the front for mounting to a fiber optictermination module or other rack structure. The module includes an openfront, which received the adapters. Preferably, the adapters snap toapertures in the major sides.

Another aspect of the present invention relates to a fiber distributionframe comprising a rack extending vertically from a bottom to a top, therack defining a left side, a right side, a front, and a rear. The frameincludes a left vertical cable guide with a side access on the left sideof the rack, and a right vertical cable guide with a side access on theright side of the rack. At least a portion of the frame defines a cabletermination area. The termination area includes: (1) a first paneldefining an array of termination locations on a front portion, the firstpanel positioned on the left side of the rack adjacent to the leftvertical cable guide, and (2) a second panel defining an array oftermination locations on a front portion, the second panel positioned onthe right side of the rack adjacent to the right vertical cable guide.The frame also includes a horizontal passageway for patch cablespositioned on the front side of the rack extending between the rightvertical cable guide, and the left vertical cable guide. The first andsecond panels are defined by adapters associated with modular units forhousing fiber couplers, such as splitters, combiners, and wave divisionmultiplexers. The modular units are selectively, partially removable toallow access to the adapters of the selected modular unit withoutinterference from adjacent modular units. Preferably, the modular unitsare retained with the frame when in the partially removed position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front, top, and right side perspective view of a firstembodiment of a fiber frame according to the present invention, with oneleft side chassis or termination module shown in exploded view, and withthe front doors open;

FIG. 2 is a front, top, and left side perspective view of one of theright side termination module from the frame of FIG. 1;

FIG. 3 is a front view of the termination module of FIG. 2;

FIG. 4 is a top view of the termination module of FIG. 2;

FIG. 5 is a front, top and right side perspective view of one of theleft side termination modules from the frame of FIG. 1;

FIG. 6 is an exploded view of the termination module of FIG. 5;

FIG. 7 is a front, top and left side perspective view of the terminationmodule of FIG. 5 showing four fiber optic modules of a first embodimentmounted within the termination module;

FIG. 8 is a front view of the termination module and fiber optic modulesof FIG. 7;

FIG. 9 is a front and left side view of the termination module of FIGS.7 and 8, taken from a position looking into the termination module inthe direction of sliding movement of each of the fiber optic modules;

FIG. 10 is a front, top and right side perspective view of thetermination module relative and fiber optic modules of FIG. 7, andshowing one of the fiber optic modules partially removed from aremainder of the fiber optic modules;

FIG. 11 is a first side view of one of the fiber optic modules shown inFIGS. 7 through 10;

FIG. 12 is an opposite side view of the fiber optic module of FIG. 11;

FIG. 13 is a front view of the fiber optic module of FIGS. 11 and 12;

FIG. 14 is a rear view of the fiber optic module of FIGS. 11 and 12;

FIG. 15 is a first end view of the fiber optic module of FIGS. 11 and12;

FIG. 16 is an opposite end view of the fiber optic module of FIGS. 11and 12;

FIG. 17 is a view of the fiber optic module of FIG. 12 with the coverportion removed showing interior structures;

FIG. 18 is an exploded perspective view of the fiber optic module ofFIGS. 11 through 17;

FIG. 19 is a perspective view of a second embodiment of a fiber opticmodule;

FIG. 20 is an exploded perspective view of the fiber optic module ofFIG. 19;

FIG. 21 is a partial cross-sectional view of a portion of the fiberoptic module of FIGS. 19 and 20 showing the connection between one ofthe adapter, and the module housing taken along lines 21-21 of FIG. 19;and

FIG. 22 is a side view of one of the ball plungers of the terminationmodule of FIGS. 1 though 10.

DETAILED DESCRIPTION

In FIG. 1, a preferred embodiment of a bay or frame 10 is shown forterminating, and managing fiber optic cables within the frame. Frame 10includes a rack 11 having a bottom 12, a top 14, and an enclosure 15having an interior 16. Hinged doors 18 allow selective access to an openfront 20 for accessing the interior 16.

Enclosure 15 of frame 10 further includes left and right sides 22, 24,and a rear 26. Left and right sides 22, 24 include cable managementstructure 28 in the form of fingers 29 for managing cables within frame10. Also, received within the interior of frame 26 is a plurality ofchassis or termination modules 30.

As shown in FIG. 1, only an upper portion of frame 10 is populated withtermination modules 30. A lower portion of frame 10 can be populatedwith additional termination modules 30, or other cable managementstructures including cable splicing. Earlier U.S. Pat. No. 6,556,763 toADC Telecommunications, Inc. shows various cable splicing structures,which can be utilized within frame 10. The disclosure of U.S. Pat. No.6,556,763 is hereby incorporated by reference.

Frame 10 further includes horizontal cable management structure 32adjacent to bottom 12 for managing cables passing between the left andright sides of frame 10. Such cabling may pass from cable managementstructure 28 positioned on each side of frame 10.

Frame 10 includes a plurality of termination modules 30. In preferredembodiments, termination modules 30 are provided with either a left handarrangement 36 or a right hand arrangement 38 for use on left and rightsides, respectively, of frame 10. The left and right hand arrangements36, 38 assist with cable management and avoidance of excess bending onthe cables. In the preferred embodiment, the cables are angled towardthe left or rights sides 22, 24 of frame 10. The left and right handarrangements 36, 38 are generally mirror images of each other.

Referring now to FIGS. 2 through 4, one of the right hand arrangements38 for termination module 30 is shown. Termination module 30 includesfirst and second ends 42, 44, first and second sides 46, 48, and a rear50. A front end 52 is generally open for receipt of fiber optic modules,as will be described below. Termination module 30 defines an interior 54for receipt of the fiber optic modules. Interior 54 includes first andsecond longitudinal guides 58, 60 for slideably receiving the fiberoptic modules in a linear direction. Termination module 30 furtherincludes a module retention mechanism 61 for retaining the fiber opticmodules with the termination module. In particular, the retentionmechanism 61 holds the fiber optic modules with the termination module30 when a selected fiber optic module 80 is partially removed from thetermination module (see FIGS. 7-10). The retention mechanism of theillustrated embodiment includes a spring biased ball plunger 64 (seealso FIG. 22). Interaction between the ball plunger 64 with the fiberoptic modules will be discussed in greater detail below. Other retentionmechanisms are possible for holding the fiber optic modules 80 in thepartially removed position.

Termination module 30 further includes structure for retaining eachfiber optic module with the termination module when the fiber opticmodule is fully inserted into interior 54. In the illustratedembodiment, termination module 30 includes apertures 66 for receipt of afastener, lock or latching element for each fiber optic module, as willbe discussed in greater detail below.

Termination module 30 includes cable management structure in the form ofcable guides 70 defining passages 71 for receiving cables extendingtoward front end 52 of termination module 30. Termination module 30further includes a curved panel 74 to further prevent cable damage bynot allowing the cables extending toward front end 52 to be bent belowthe minimum bend radius which might cause cable damage and loss ofperformance. Fingers 29 of frame 10, sides 22, 24 and cable guides 70define vertical channels for cables extending to and from terminationmodules 30. The cables can extend vertically upward out of frame 10, ordownward into the floor of a raised floor system. Alternatively, thecables can pass horizontally from one side of frame 10 to the other, orto other adjacent frames.

Referring now to FIGS. 7 through 10, one of termination modules 30 isshown with a plurality of fiber optic modules 80 received withininterior 54. Additional fiber optic modules 80 can populate theremaining open space of termination module 30. As shown in FIGS. 7through 9, each fiber optic module 80 presents a plurality of connectionlocations 82 defined by fiber optic adapters 84. Adapters 84 can be anyof a variety of fiber optic adapters desired for use in frame 10. Inparticular, fiber optic adapters such as SC, E2000, LC or LX.5 (by ADCTelecommunications, Inc., and shown in U.S. Pat. Nos. 5,883,995 and6,142,676). Alternatively, other adapters can be utilized. Adapters 84define the connection locations 82 for connecting to connectors on theends of fiber optic cables. On an opposite end of adapters 84, disposedwithin fiber optic modules 80, adapters 84 also receive a fiber opticconnector associated with the internal circuitry of fiber optic modules80.

Still referring to FIGS. 7 though 9, fiber optic modules 80 withintermination module 30 present a dense arrangement of the connectionlocations 82. Should access to a selected connection location 82 bedesired, such as for connecting or disconnecting a cable connector toone of adapters 84, an operator may have a difficult time accessing theselected connector and adapter without disrupting other connections.Referring now to FIG. 10, one of fiber optic modules 80 is shownpartially removed from termination module 30 so as to improve the easeof access by the operator to the selected connection location 82. InFIG. 10, the lowermost fiber optic module 80 is shown partially removedto improve access to adapters 84 of the partially removed module.

Termination module 30 cooperates with each fiber optic module 80 to holdfiber optic modules 80 in the fully inserted position. Terminationmodule 30 also cooperates with each fiber optic module 80 to allow forpartial removal of selected fiber optic modules 80 as shown in FIG. 10.A latch 90 on each module 80 securely retains each fiber optic module 80with termination module 30. Latch 90 as shown is a swell latch whichcooperates with apertures 66 of termination module 30. When latch 90 isreleased, by flipping the latch, the selected fiber optic module 80 canbe removed from termination module 30 if desired.

Fiber optic module 80 can also be retained in the position shown in FIG.10 for the lowermost fiber optic module 80. As will be described below,fiber optic module 80 includes structure which cooperates with the ballplunger 64 of termination module 30 to hold the partially removed fiberoptic module 80 to termination module 30.

Referring now to FIGS. 11 though 18, one of fiber optic modules 80 isshown in greater detail. Module 80 has a housing 94 including first andsecond major sides 96, 98, and first and second minor sides 100, 102. Arear end 104 cooperates with major sides 96,98 and minor sides 100, 102to define an interior 106 for housing fiber optic components and cables.FIGS. 19-21 show a second embodiment of a fiber optic module 280, with asimilar housing construction. Module 280 includes the same housing 94,but uses different adapters 284.

Major sides 96, 98 and minor sides 100, 102 define an open front end108, which receives fiber optic adapters 84. If desired, a blank 116 canbe mounted at front end 108 instead of an adapter 84. As shown, module80 has room for nine adapters or blanks.

Preferably, module 80 includes first and second front flanges 118, 120.As shown, front flange 118 holds latch 90. Latch 90 is a swell latchincluding a pivoting handle 122, and an expandable end 124 for receiptin opening 66 in termination module 30. Other latches, locks orfasteners can be used to retain module 80 in the fully insertedposition.

In the preferred embodiment of fiber optic module 80, minor sides 100,102, major side 98, and rear end 104 are integrally formed from a singlehousing structure or main portion 126, such as bent sheet metal. Thissingle housing structure 126 can also include front flanges 118, 120.Further in the preferred embodiment, major side 96 includes a coverportion 128, and a front end portion 130. In the preferred embodiment,front end portion 130 includes a U-shape with ends 132, 134 and acentral extension 136 positioned therebetween (see also FIG. 20).

Front end portion 130 and cover portion 128 are preferably also madefrom convenient structures, including sheet metal. Threaded fasteners138 mount cover portion 128 to main portion 126 of fiber optic module80. Threaded fasteners 139 further mount front end portion 130 to mainportion 126. Fastener holes 103 in minor sides 100, 102 are preferablyelongated to allow for a variety of spacings of front end portion 130relative to main portion 126. Such a feature is desirable to accommodateadapters of differing dimensions for different modules. Main portion 126includes a cutout 146 with projections 147 on opposite ends whichreceives end portion 130.

As noted above adapters 84 mount to front end 108 of fiber optic module80. In the preferred embodiment, a line of apertures 140 is provided ineach of major sides 96, 98 so as to receive attachment structure of eachadapter 84. In the preferred embodiment, adapters 84 include projections86 such as spring arms or latch portions or other structures, which arereceived in apertures 140. Similarly, blank 116 includes projections 117for receipt in aperture 140 (see FIG. 20). By defining a front end 108of fiber optic module 80 by the edges of major sides 96, 98, a thinnermodule can be provided. Thinner modules allow for greater densities ofadapters 84 in a given footprint within frame 10 and termination module30. With increased density may come the likelihood of more difficulty inaccessing individual adapters 84. The present invention allows forpartial removal of the fiber optic module 80 at the selected time. Theoperator can individually access the selected module 80 withoutdisrupting other cables and connections on adjacent modules. Preferablyfront end portion and major side 98 are made from thin sheet metal suchas aluminum, at least 0.080 inches thick, so as to engage the springarms of the adapter.

Module 80 includes flanges 142, 144 defined by cover portion 128.Flanges 142, 144 cooperate with first and second longitudinal guides 58,60 of termination module 30 to slideably move into and out oftermination module 30. In the preferred embodiment, flanges 142, 144 areplanar structures extending beyond minor sides 100, 102 of fiber opticmodule 80. Longitudinal guides 58, 60 of termination module 30 are shownin one possible implementation including channel defining inserts 148mounted on first interior panel 149 for first longitudinal guides 58,and slots 150 in second interior panel 152 defining second longitudinalguides 60. Both channel defining inserts 148 and slots 150 each receiveone of flanges 142, 144.

Termination module 30 includes various panel elements 42, 44, 46, 48,149, and 152 that can be made from any convenient housing material, suchas sheet metal. Supports 166, 168 strengthen first and second interiorpanels 149, 152 in the preferred embodiment.

Termination module 30 preferably angles the adapters 84 toward cableguides 70. Such angling helps avoid excessive bends on the front cablesextending toward fiber optic modules 80 positioned in termination module30. Such angling is achieved by angling longitudinal guides 58, 60toward cable guides 70. FIG. 8 shows a view into termination module 30perpendicular to the planar rear 50. As can be seen in FIG. 8, inserts148 and slots 150 are not perpendicularly positioned, but at a slightangle, such as 5 degrees, relative to rear 50. FIG. 9 shows a view oftermination module 30 from the slight angle toward guides 70 showing theinserts 148 and slots viewed perpendicularly.

It is further preferred that fiber optic module 80 can be utilizedeither in the left hand arrangement 36 or the right hand arrangement 38for termination modules 30 by merely flipping the module 180 degreesupside down from the left side to the right side of frame 10. Left andright hand arrangements 36, 38 are constructed so as to accommodate theflanges 142, 144 as modules 80 are flipped between the left and rightsides.

Referring now to FIGS. 17 and 18, the fiber optic circuitry 114 isillustrated within interior 106 of fiber optic module 80. Fiber opticcouplers 164 are held by holders 156. A mounting plate 188 mounts eachholder 156 to major side 98, such as with threaded fasteners (notshown). Internal cables 158 connect to rear ends of the adapters 84through mating connectors (not shown). A variety of fiber opticcircuitry can be utilized including fiber optic splitters, WDM's,DWDM's, and any other passive optical circuitry. In some embodiments, itmay be desirable to have straight pass through connections, withmonitoring ports. In that case, there would be one input, one output andone monitor port per circuit. Module 80 could hold three of thosecircuits. FIG. 17 shows a 1×3 optical splitter circuit 162. In FIG. 17,module 80 could house two 1×3 optical splitters, with one blank 116.Schematic label 169 can be added to module 80 to illustrate or describethe circuit functions for the operator.

Mounting tabs 164 for mounting main portion 126 to cover portion 128 arealso used to retain cables 158 during assembly, before cover portion 128is closed. Cable clip 186 assists with cable management.

Referring now to FIGS. 19 through 21, second embodiment of a fiber opticmodule 280 is shown. One difference over fiber optic module 80 is shownwith respect to adapters 284. Adapters 284 are SC type, whereas adapters84 are E2000 type. FIG. 21 shows in greater detail receipt ofprojections, e.g., spring arms 286, within apertures 140 of modulehousing 94. If adapters 284 were taller or shorter than adapters 84, thespacing between extension 136 and major side 96 can be adjusted withelongated holes 103 in minor sides 100, 102.

Referring now to FIG. 22, an example ball plunger 64 is shown includinga housing 170 which holds a ball 172 with a projecting end 174. Aninternal spring 176 biases ball 172 to the position shown. Ball plunger64 is positioned within interior 54 of termination module 30 to retaineach module 80 with termination module 30. Ball plungers 64 arepress-fit into panel 152 of termination module 30. When fiber opticmodule 80 is partially removed from interior 54 of termination module30, end 174 of ball 172 is received opening 110 in minor side 100 ofmodule 80. With ball plunger 64 engaging opening 110, module 80 isretained by termination module 30 in the partially removed position. Theengagement of ball plunger 64 with opening 110 provides a lock forretaining or holding module 80 while the operator accesses the desiredconnection location. In the case of the operator removing a connectorfrom one adapter 84, ball plunger 64 holds module 80 in the partiallyremoved position so that the operator can pull the connector from theselected adapter 84. In so doing, the operator does not need to alsohold module 80 to retain module 80 with termination module 30. The forceneeded to disconnect the connector from the selected adapter 84 is lessthan the force which holds fiber optic module 80 with termination module30.

Should the operator desire to remove fiber optic module 80 entirely fromtermination module 30, the force provided by ball plunger 64 engagingopening 110 can be overcome by the operator grasping the front end 108of module 80 and pulling outwardly.

In the preferred embodiment, minor side 100 of fiber optic module 80 isfurther provided with a second opening 112 for holding end 174 of ball172 when module 80 is fully inserted into termination module 30. Suchretention feature is optional since latch 90 retains each fiber opticmodule 80 with the termination module 30 in the fully inserted position.However, with a retainer arrangement utilizing ball plungers 64, somestress relief may be needed by termination module 30 so as to not bowout panel 152. If desired, second opening can be smaller than firstopening 110.

Other retention mechanisms are anticipated for holding and retainingfiber optic modules 80 with termination modules 30 in the partiallyremoved positions. For example, a leaf spring can project inwardly frompanel 152 for engagement with structure on fiber optic module 80,including openings in minor side 102, or flange 144.

While the preferred adapters 84, 284 and others noted herein includeopposed projections for mounting to apertures 140 in each of major sides96, 98, other adapters can be used. For example, ST and FC type may beused if an appropriate adapter member is used to link each adapter tomodule 80 and apertures 140.

It is to be appreciated that the fiber optic module retention featuresof the present invention can be used with other frames besides frame 10including termination modules 30. Also, termination modules 30, with thefiber optic module retention mechanism for holding the modules in thepartially removed position, can be used with other fiber optic modulesbesides modules 80, 280. In some applications, it may be desirable toprovide modules with plural rows of adapters.

The above specification, examples and data provide a completedescription of the manufacture and use of the composition of theinvention. Since many embodiments of the invention can be made withoutdeparting from the spirit and scope of the invention, the inventionresides in the claims hereinafter appended.

1-12. (canceled)
 13. A fiber optic module adapted to be held by a frame,the fiber optic module comprising: a housing including a top surface anda bottom surface extending parallel to each other, the top and bottomsurfaces interconnected by two spaced-apart side surfaces extendingparallel to each other, the top surface, bottom surface, and sidesurfaces sides extending between front and rear ends of the housing, thefront end being open and defined by edges of the surfaces; an adapterretainer mounted at the open front end of the housing, the adapterretainer defining a plurality of apertures, the adapter retainer beingsized to fit within a perimeter defined by the open front of thehousing; a plurality of fiber optic adapters mounted to the adapterretainer at the front end of the housing, each fiber optic adapterhaving a port facing forwardly of the housing; and a front flangecoupled to the housing at the open front end, the front flange beingconfigured to latch the housing to a frame.
 14. The fiber optic moduleof claim 13, wherein the housing defines a first side flange thatextends planar with the top surface of the housing past a first of theside surfaces.
 15. The fiber optic module of claim 14, wherein the firstside flange extends planar with the top surface along a directionrunning between the front end of the housing and the rear end of thehousing.
 16. The fiber optic module of claim 14, wherein the housingalso defines a second side flange that planar with the top surface ofthe housing past a second of the side surfaces.
 17. The fiber opticmodule of claim 13, wherein one of the side surfaces defines first andsecond openings, the first opening being positioned further from therear end of the housing than the second opening, each of the first andsecond openings being sized to receive a ball end of a spring loadedball plunger.
 18. The fiber optic module of claim 17, wherein the firstand second openings are aligned along a direction running between thefront end of the housing and the rear end of the housing.
 19. The fiberoptic module of claim 17, wherein the first opening is smaller than thesecond opening.
 20. The fiber optic module of claim 13, wherein thehousing encloses at least one internal cable extending from a first endto a second end, the first end being plugged into rear ports of thefiber optic adapters.
 21. The fiber optic module of claim 20, whereinthe housing also encloses a passive optical device to which the secondend of the internal cable is optically coupled.
 22. The fiber opticmodule of claim 21, wherein the passive optical device comprises anoptical splitter.
 23. The fiber optic module of claim 21, wherein thepassive optical device comprises a straight through connector.
 24. Thefiber optic module of claim 13, wherein the top surface of the housingdefines a second plurality of apertures that align with the aperturesdefined by the adapter retainer.
 25. The fiber optic module of claim 24,wherein each of the fiber optic adapters includes projections that fitinto the apertures of the adapter retainer and the top surface.
 26. Thefiber optic module of claim 13, further comprising a second front flangecoupled to the housing at the open front end opposite the first frontflange, the second front flange being smaller than the first frontflange.
 27. The fiber optic module of claim 13, wherein the housingencloses holders that are configured to hold couplers.